I have a 20,000gal gunite pool that's about 20 years old and in need of new plaster and tile. It also has a concrete deck with Kool Deck that is in pretty rough shape. I am wondering what options are available to repair the Kool Deck. Is it possible to just put blue stone over it or does the concrete have to come out first? Can the "loose" Kool Deck be removed and then it or something like it re-applied? Is there anything I need to look out for when hiring a pool builder to do this type of work?